@article{econhot_econhot-cited-4f697dbcb35a34e9,
  title = {Assignment to Treatment Group on the Basis of a Covariate},
  author = {Donald B. Rubin},
  journal = {Journal of Educational Statistics},
  year = {1977},
  volume = {2},
  number = {1},
  pages = {1-26},
  doi = {10.3102/10769986002001001},
  url = {https://doi.org/10.3102/10769986002001001}
}